Do we trivialize a sublime feeling if we appreciate its dependence on the brain? Not in the least. Its significance does not depend on its being a soul state or a brain state...Humility bids us to take ourselves as we are; we do not have to be cosmically significant to be genuinely significant.

Paul Erdős, in a standard greeting he would make when he was not contemplating some mathematical problem, as quoted in My Brain Is Open : The Mathematical Journeys of Paul Erdos (1998) by Bruce Schechter, p. 10

If the human brain were so simple that we could understand it, we would be so simple that we couldn't.

Emerson M. Pugh, as quoted in The Biological Origin of Human Values

The brain is a mystery; it has been and still will be. How does the brain produce thoughts? That is the central question and we have still no answer to it.

People who had damage to the right cerebral hemisphere were unable to recognise simple patterns, or enjoy music, but they could still speak normally. People with left-brain damage were able to recognise patterns, but their speech was impaired. Obviously, then, the left deals with language, and you would expect a split-brain patient to be unable to read with his right eye (connected, remeber, to the opposite side of the brain). Sperry's patient was also unable to write anything meaningful (i.e., complicated) with his left hand. They noticed another oddity. if the patient bumped into something with his left side, he did not notice. And the implications were very odd indeed. Not only did the split-brain operation give the patient two separate minds; it also seemed to restrict his identity, or ego, to the left side. When they placed an object in his left hand, and asked him what he was holding, he had no idea. Further experiments underlined the point. If a split-brain patient is shown two different symbols -- say a circle and a square -- with each eye, and is asked to say what he has just seen, he replies, 'A square'. Asked to draw with his left hand what he has seen, and he draws a circle. Asked what he has just drawn, he replies: 'A square'. And when one split-brain patient was shown a picture of a nude male with the right-brain, she blushed; asked why she was blushing, she replied truthfully: 'I don't know'. The implications are clearly staggering. The person you call 'you' lives in the left side of your brain. And a few centimeters away there is another person, a completely independent identity. Where language is concerned, this other person is almost an imbecile. In other respects, he is more competent than the inhabitant of the left-brain; for example, he can make a far more accurate perspective drawing of a house. In effect. the left-brain person is a scientist, the right-brain an artist.